Chronic cardiac disease is a leading cause of mortality and morbidity in the developed world. One type of chronic cardiac disease is cardiomyopathy, which is actually a diverse group of diseases characterized by myocardial dysfunction that is not related to the usual causes of heart disease such as coronary atherosclerosis, valvular dysfunction and hypertension. Cardiomyopathies are categorized hemodynamically into dilated, hypertrophic, restrictive and obliterative cardiomyopathy, and can be of known or idiopathic etiology. Among the etiologies of dilated cardiomyopathy are pregnancy, drugs and toxins, such as alcohol, cocaine and chemotherapeutic agents (including doxorubicin and daunorubicin, dactinomycin, dacarbazine, cyclophosphamide, mitomycin, and anthracycline), and infectious and autoimmune processes. Hypertrophic cardiomyopathy is hereditary in more than 50% of cases and has a distinctive pattern of myocardial hypertrophy (thickening of muscle) usually with a pattern of asymmetrical thickening of the interventricular septum (also called asymmetrical septal hypertrophy). Restrictive cardiomyopathies are usually the product of an infiltrative disease of the myocardium, such as amyloidosis, hemochromatosis or a glycogen storage disease, and may also be seen in certain diabetic patients. Obliterative cardiomyopathy can be caused by endomyocardial fibrosis and hypereosinophilic syndrome. A common complication of all of the cardiomyopathies is progressive congestive heart failure.
Congestive heart failure is often defined as the inability of the heart to deliver a supply of oxygenated blood sufficient to meet the metabolic needs of peripheral tissues at normal filling pressures. Chronic congestive heart failure can result as a consequence of coronary artery disease, cardiomyopathy, myocarditis, aortic stenosis, hypertension, idiopathic asymmetrical septal hypertrophy, coarctation of the aorta, aortic regurgitation, mitral regurgitation, left-to-right shunts, hypertrophied muscle, pericardial tamponade, constrictive pericarditis, mitral stenosis, left atrial mzxoma, left atrial thrombus, cor triatriatum and numerous other conditions. Congestive heart failure is generally distinguished from other causes of inadequate oxygen delivery, such as circulatory collapse from hemorrhage or other causes of severe volume loss, congestion caused by fluid overload and high-output failure caused by increased peripheral demands which occurs in conditions such as thyrotoxicosis, arteriovenous fistula, Paget's disease and anemia. Therapy for congestive heart failure typically focuses on the treating the underlying etiology and the symptoms of fluid overload and heart failure. Chronic congestive heart failure that persists after correction of reversible causes is treated with diuretics (including thiazides such as chlorothiazide and hydrochlorothiazide, loop diuretics such as ethacrynic acid, furosemide, torsemide and bumetanide, potassium sparing agents such as spironolactone, triamterene and amiloride, and others such as metolazone and other quinazoline-sulfonamides), vasodilators (including nitroglycerin, isosorbide dinitrate, hydralazine, sodium nitroprusside, prostacyclin, captopril, enalapril, lisinopril, quinapril and losartan), positive inotropic agents (such as digitalis or digoxin), occasionally beta blockers, or combinations of these measures.
Recent studies indicate that an increase in pro-inflammatory cytokines is seen in diverse cardiac diseases, including congestive heart failure, cardiomyopathy, and myocarditis. Hegewisch S, et al. Lancet 1990;2:294–295; Levine B, et al., N.Engl.J.Med. 1990;323 (4):236–241; Mann D L, et al., Chest 1994;105:897–904; and Givertz M M, et al., Lancet 1998;352:34–38 For example, the cytokine tumor necrosis factor-α (TNF) is synthesized by human cardiac myocytes, and the level of TNF expression correlates with the degree of cardiac dysfunction in patients. Torre-Amione G, et al., J.Am.Coll.Cardiol. 1996;27:1201–1206; Torre-Amione G, R D, et al. Circulation 1995;92:1487–1493; and Torre-Amione G, et al., Circulation 1996;93:704–711 In animals, synthesis of TNF by the heart is itself sufficient to cause cardiomyopathy and lethal cardiac failure. Bryant D, et al., Circ. 1998;97:175–183 and Kubota T, et al. J.Am.Coll.Cardiol. 1997;346A(Abstract) Furthermore, early human trials have demonstrated that antagonism of TNF improves cardiac failure in humans with NYHA Class III heart failure or idiopathic dilated cardiomyopathy. Deswal et al., Circulation 96: I–323 (1997); and Sliwa et al., Lancet 351: 1091–1093 (1998) However, the primary stimulus for cytokine secretion remains unknown.
Bacterial endotoxin, or lipopolysaccharide (LPS), is a primary inducer of TNF production during sepsis. With respect to cardiac diseases, the role of endotoxin has been examined primarily in the context of cardiopulmonary bypass, driven by the hypothesis that endotoxin may be present in the extracorporeal circuit, or may be translocated across the intestine secondary to non-pulsatile, low flow perfusion. Riddington D W, et al. JAMA 1996;275:1007–1012 and Wan S, et al., Chest 1997;112:676–692 These studies have demonstrated only transient low-level endotoxemia during cardiopulmonary bypass, with rapid resolution following completion of cardiopulmonary bypass in the majority of patients. Nilsson L, J Thorac Cardiovasc Surg 1990;100:777–780; Casey W F, Crit.Care Med. 1992;20 (8):1090–1096; Khabar K S, et al., Clin Immunol Immunopathol 1997;85:97–103; Jansen N J, Ann Thorac Surg 1992;54:744–747. Bennett-Guerrero E et al., JAMA 1997;277:646–650 reported that lower levels of anti-endotoxin antibodies pre-operatively were associated with an increased risk of post-operative complications and hypothesized that this difference was due to a poor immunity to endotoxin.
Investigators have thus far failed to demonstrate, or failed to attempt to demonstrate, persistent endotoxemia in a majority of patients with cardiac disease Nilsson L, J Thorac Cardiovasc Surg 1990;100:777–780; Casey W F, Crit.Care Med. 1992;20 (8): 1090–1096; Khabar K S, et al., Clin Immunol Immunopathol 1997;85:97–103; Jansen N J, Ann Thorac Surg 1992;54:744–747. See also Niebauer J, Eur. Heart J. 1998;19:174, which reported elevated levels of plasma endotoxin in adults with edemetous chronic congestive heart failure that was not associated with elevated levels of LBP or anti-endotoxin antibodies (indicators of long-term endotoxin exposure).
BPI is a protein isolated from the granules of mammalian polymorphonuclear leukocytes (PMNs or neutrophils), which are blood cells essential in the defense against invading microorganisms. Human BPI protein has been isolated from PMNs by acid extraction combined with either ion exchange chromatography [Elsbach, J. Biol. Chem., 254:11000 (1979)] or E. coli affinity chromatography [Weiss, et al., Blood, 69:652 (1987)]. BPI obtained in such a manner is referred to herein as natural BPI and has been shown to have potent bactericidal activity against a broad spectrum of gram-negative bacteria. The molecular weight of human BPI is approximately 55,000 daltons (55 kD). The amino acid sequence of the entire human BPI protein and the nucleic acid sequence of DNA encoding the protein have been reported in FIG. 1 of Gray et al., J. Biol. Chem., 264:9505 (1989), incorporated herein by reference. The Gray et al. amino acid sequence is set out in SEQ ID NO: 1 hereto. U.S. Pat. No. 5,198,541 discloses recombinant genes encoding and methods for expression of BPI proteins, including BPI holoprotein and fragments of BPI.
BPI is a strongly cationic protein. The N-terminal half of BPI accounts for the high net positive charge; the C-terminal half of the molecule has a net charge of −3. [Elsbach and Weiss (1981), supra.] A proteolytic N-terminal fragment of BPI having a molecular weight of about 25 kD possesses essentially all the anti-bacterial efficacy of the naturally-derived 55 kD human BPI holoprotein. [Ooi et al., J. Bio. Chem., 262: 14891–14894 (1987)]. In contrast to the N-terminal portion, the C-terminal region of the isolated human BPI protein displays only slightly detectable anti-bacterial activity against gram-negative organisms. [Ooi et al., J. Exp. Med., 174:649 (1991).] An N-terminal BPI fragment of approximately 23 kD, referred to as “rBPI23,” has been produced by recombinant means and also retains anti-bacterial activity against gram-negative organisms. [Gazzano-Santoro et al., Infect. Immun. 60:4754–4761 (1992).] An N-terminal analog of BPI, rBPI21, has been produced as described in Horwitz et al., Protein Expression Purification, 8:28–40 (1996).
The bactericidal effect of BPI was originally reported to be highly specific to gram-negative species, e.g., in Elsbach and Weiss, Inflammation: Basic Principles and Clinical Correlates, eds. Gallin et al., Chapter 30, Raven Press, Ltd. (1992). The precise mechanism by which BPI kills gram-negative bacteria is not yet completely elucidated, but it is believed that BPI must first bind to the surface of the bacteria through electrostatic and hydrophobic interactions between the cationic BPI protein and negatively charged sites on LPS. In susceptible gram-negative bacteria, BPI binding is thought to disrupt LPS structure, leading to activation of bacterial enzymes that degrade phospholipids and peptidoglycans, altering the permeability of the cell's outer membrane, and initiating events that ultimately lead to cell death. [Elsbach and Weiss (1992), supra]. LPS has been referred to as “endotoxin” because of the potent inflammatory response that it stimulates, i.e., the release of mediators by host inflammatory cells which may ultimately result in irreversible endotoxic shock. BPI binds to lipid A, reported to be the most toxic and most biologically active component of LPS.
BPI protein products have a wide variety of beneficial activities. BPI protein products are bactericidal for gram-negative bacteria, as described in U.S. Pat. Nos. 5,198,541 and 5,523,288, both of which are incorporated herein by reference. International Publication No. WO 94/20130 (incorporated herein by reference) proposes methods for treating subjects suffering from an infection (e.g. gastrointestinal) with a species from the gram-negative bacterial genus Helicobacter with BPI protein products. BPI protein products also enhance the effectiveness of antibiotic therapy in gram-negative bacterial infections, as described in U.S. Pat. No. 5,523,288 and International Publication No. WO 95/08344 (PCT/US94/11255), which are incorporated herein by reference. BPI protein products are also bactericidal for gram-positive bacteria and mycoplasma, and enhance the effectiveness of antibiotics in gram-positive bacterial infections, as described in U.S. Pat. Nos. 5,578,572 and 5,783,561 and International Publication No. WO 95/19180 (PCT/US95/00656), which are incorporated herein by reference. BPI protein products exhibit anti-fungal activity, and enhance the activity of other anti-fungal agents, as described in U.S. Pat. No. 5,627,153 and International Publication No. WO 95/19179 (PCT/US95/00498), and further as described for anti-fungal peptides in U.S. Pat. No. 5,858,974, which is in turn a continuation-in-part of U.S. application Ser. No. 08/504,841 filed Jul. 20, 1994 and corresponding International Publication Nos. WO 96/08509 (PCT/US95/09262) and WO 97/04008 (PCT/US96/03845), all of which are incorporated herein by reference. BPI protein products exhibit anti-protozoan activity, as described in U.S. Pat. No. 5,646,114 and International Publication No. WO 96/01647 (PCT/US95/08624), which are incorporated herein by reference. BPI protein products exhibit anti-chlamydial activity, as described in co-owned, co-pending U.S. application Ser. No. 08/694,843 filed Aug. 9, 1996 and WO 98/06415 (PCT/US97/13810), which are incorporated herein by reference. Finally, BPI protein products exhibit anti-mycobacterial activity, as described in co-owned, co-pending U.S. application Ser. No. 08/626,646 filed Apr. 1, 1996, which is in turn a continuation of U.S. application Ser. No. 08/285,803 filed Aug. 14, 1994, which is in turn a continuation-in-part of U.S. application Ser. No. 08/031,145 filed Mar. 12, 1993 and corresponding International Publication No. WO94/20129 (PCT/US94/02463), all of which are incorporated herein by reference.
The effects of BPI protein products in humans with endotoxin in circulation, including effects on TNF, IL-6 and endotoxin are described in U.S. Pat. No. 5,643,875, which is incorporated herein by reference.
BPI protein products are also useful for treatment of specific disease conditions, such as meningococcemia in humans (as described in co-owned, co-pending U.S. application Ser. No. 08/644,287 filed May 10, 1996 and continuation Ser. No. 08/927,437 filed Sep. 10, 1997 and International Publication No. WO97/42966 (PCT/US97/08016), all of which are incorporated herein by reference), hemorrhagic trauma in humans, (as described in U.S. Pat. No.5,756,464, U.S. application Ser. No. 08/862,785 filed May 23, 1997 and corresponding International Publication No. WO 97/44056 (PCT/US97/08941), all of which are incorporated herein by reference), burn injury (as described in U.S. Pat. No. 5,494,896, which is incorporated herein by reference), ischemia/reperfusion injury (as described in U.S. Pat. No. 5,578,568, incorporated herein by reference), and liver resection (as described in co-owned, co-pending U.S. application Ser. No. 08/582,230 filed Jan. 3, 1996, which is in turn a continuation of U.S. application Ser. No. 08/318,357 filed Oct. 5, 1994, which is in turn a continuation-in-part of U.S. application Ser. No. 08/132,510 filed Oct. 5, 1993, and corresponding International Publication No. WO 95/10297 (PCT/US94/11404), all of which are incorporated herein by reference).
BPI protein products also neutralize the anti-coagulant activity of exogenous heparin, as described in U.S. Pat. No. 5,348,942, incorporated herein by reference, and are useful for treating chronic inflammatory diseases such as rheumatoid and reactive arthritis and for inhibiting angiogenesis and for treating angiogenesis-associated disorders including malignant tumors, ocular retinopathy and endometriosis, as described in U.S. Pat. Nos. 5,639,727, 5,807,818 and 5,837,678 and International Publication No. WO 94/20128 (PCT/US94/02401), all of which are incorporated herein by reference.
BPI protein products are also useful in antithrombotic methods, as described in U.S. Pat. No. 5,741,779 and U.S. application Ser. No. 09/063,465 filed Apr. 20, 1998 and corresponding WO 97/42967 (PCT/US7/08017), all of which are incorporated herein by reference.